FIG. 1 shows different known compound bodies and implicitly the production processes thereof. FIG. 1a shows the vacuum-tight passage of a wire 10 through a glass wall 15. Here, the wire is preglazed as indicated by the dashed outline 16. Thereafter, it is melted into a glass tube end (FIG. 1a) or in a glass plate (FIG. 1b). In this case, glass and metal are chosen such that the courses of their coefficients of thermal expansion are as similar as possible from melting point to cooling (“fully adapted”). However, if this full adaptation is not possible, tension cracks may occur in the glass or the wire can separate from the glass. If for directly melting the metal into the glass the misadaptation therebetween is excessively great, the tension can be compensated for step-wise by intermediate glasses 17a to 17c and/or by a dome geometry 17d, as shown in FIG. 1c. 
FIG. 1d shows what is called a “cutting edge glassing”, FIG. 1e shows “foil squeezing”. Here, each metal partner 11, 13 is thin enough to compensate for the optionally occurring deformations so that no dangerous tensions occur in the glass.
FIG. 1f shows the principle of “pressure glassing”. Wire and metal plate 12 have a coefficient of expansion somewhat higher than that of the melting glass 15. However, no tension cracks occur in the glass part 15 because following melting-in the metal 12 is shrunk onto the glass 15, thus producing a compressive stress.
FIG. 1g shows an embodiment in which a metallic cap 11 is stuck on a glass tube 15 by means of an epoxy adhesive 18.
FIG. 1h shows the connection of two glass s 15, 14 by means of indium 19.
The compound bodies shown in FIG. 1 have one or more of the following drawbacks:                The classical melting-in metals tungsten, molybdenum, iron/nickel alloys, iron/cobalt/nickel alloys and copper-clad wires are relatively expensive since they have to be drawn without any defects and be provided with special coatings so as to obtain a successful glass/metal connection.        Glasses have to be used which, e.g. as regards their strain properties, are adapted as accurately as possible to the melted-in metals. This limits the selection of the glass.        The use of intermediate glasses (FIG. 1c) often calls for glass-blowing handicraft and is otherwise time-consuming and expensive.        The production of thin, deep-drawn parts (FIG. 1d) or the use of pin/sheet/pin (FIG. 1e) is expensive.        Indium-containing solders (FIG. 1h) are expensive and not temperature-resistant.        Alloys made of iron/cobalt/nickel have a high specific electric resistance.        Adhesions (FIG. 1g) are not durable and water-permeable.        
DE-AS 2150092 discloses a process for connecting glass or ceramics with metals. The metal used is an aluminum-containing copper alloy having an aluminum oxide-containing surface layer. The drawback of this approach is the little ductility and thus poor resistance to thermal shocks and the insufficient connection between glass and metal resulting from the aluminum oxide.
DE-AS 2018752 discloses a process for the gas-tight connection of metal and glass surfaces. The process operates within temperature ranges below the melting point of the metal and forces the surfaces to be connected against each other at high pressure. The drawback of this process is that the resulting connections are insufficient and that it can only be used with rather simple geometries. There is only little resistance to thermal shocks.
DE 3827318A1 discloses a seal between ceramic and metallic articles. Here, a metallic compound sealing element having aluminum as the main constituent is provided with a coating consisting of another metal. The metal is then contacted with the other components and heated above the melting point. The drawback is the elaborate production, the insufficient deformability and the little ductility on the contact surface, which results in a deteriorated resistance to thermal shocks.
It is the object of this invention to provide a compound body which has a firm, durable and vacuum-tight connection resistant to thermal shocks and can be produced at a low price, and a process for the production of a mechanical connection with which a compound body having the above properties can be produced.
This object is achieved by the features of the independent claims. Dependent claims are directed to preferred embodiments of the invention.